title: Structural characterization of cleaved, soluble HIV-1 envelope glycoprotein trimers.
abstract: Human immunodeficiency virus type 1 (HIV-1) infection is a significant global public health problem for which development of an effective prophylactic vaccine remains a high scientific priority. Many concepts for a vaccine are focused on induction of appropriate titers of broadly neutralizing antibodies (bNAbs) against the viral envelope (Env) glycoproteins gp120 and gp41, but no immunogen has yet accomplished this goal in animals or humans. One approach to induction of bNAbs is to design soluble, trimeric mimics of the native viral Env trimer. Here, we describe structural studies by negative-stain electron microscopy of several variants of soluble Env trimers based on the KNH1144 subtype A sequence. These Env trimers are fully cleaved between the gp120 and gp41 components and stabilized by specific amino acid substitutions. We also illustrate the structural consequences of deletion of the V1/V2 and V3 variable loops from gp120 and the membrane-proximal external region (MPER) from gp41. All of these variants adopt a trimeric configuration that appropriately mimics native Env spikes, including the CD4 receptor-binding site and the epitope for the VRC PG04 bNAb. These cleaved, soluble trimer designs can be adapted for use with multiple different env genes for both vaccine and structural studies.
authors.affiliation: Department of Integrative Structural and Computational Biology, The Scripps Research Institute, La Jolla, California, USA.
authors.forename: Reza
authors.initials: R
authors.lastname: Khayat
authors.forename: Jeong Hyun
authors.initials: JH
authors.lastname: Lee
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Julien
authors.forename: Albert
authors.initials: A
authors.lastname: Cupo
authors.forename: Per Johan
authors.initials: PJ
authors.lastname: Klasse
authors.forename: Rogier W
authors.initials: RW
authors.lastname: Sanders
authors.forename: John P
authors.initials: JP
authors.lastname: Moore
authors.forename: Ian A
authors.initials: IA
authors.lastname: Wilson
authors.forename: Andrew B
authors.initials: AB
authors.lastname: Ward
mesh_terms: D016915:AIDS Vaccines / Q000737:chemistry / Q000235:genetics / Q000276:immunology; D019943:Amino Acid Substitution; D057134:Antibodies, Neutralizing / Q000096:biosynthesis; D015704:CD4 Antigens / Q000737:chemistry; D015483:HIV Antibodies / Q000096:biosynthesis; D015699:HIV Envelope Protein gp120 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D015700:HIV Envelope Protein gp41 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D015497:HIV-1 / Q000737:chemistry* / Q000235:genetics / Q000276:immunology; D006801:Humans; D021621:Imaging, Three-Dimensional; D008958:Models, Molecular; D018716:Molecular Mimicry; D020836:Protein Structure, Quaternary; D012995:Solubility
chemical_list: D016915:AIDS Vaccines; D057134:Antibodies, Neutralizing; D015704:CD4 Antigens; D015483:HIV Antibodies; D015699:HIV Envelope Protein gp120; D015700:HIV Envelope Protein gp41; C514793:gp120 protein, Human immunodeficiency virus 1; C514787:gp41 protein, Human immunodeficiency virus 1